Engine/Transmission (1994 - 1998) Engine using oil, need opinions

[GAmes]

Up to a quart in 1000 miles is considered "normal" by most manufactures for warranty purposes, you're not burning much more than that.



If your engine suddenly started using more oil, and it's not leaking, it could be a broken oil ring. Any unusual operating conditions prior to the oil consumption increase?

The drastic increase in consumption was not preceded by anything abnormal. I was using 1 to 2 quarts every 5000 miles, some of it from leakage. All of a sudden I used a qt in 1500 miles. I had the IP fixed and replaced my oil pan gasket. That was 5000 miles ago. The next long drive was 1600 miles and I used 2 qts. I replaced the valve seals. Now it is much worse. Put a qt in in Ft. Stockton, another 1 1/2 in Tucson. 2 1/2 qts in 900 miles. Something is definitely broke. I'll deliver in Phoenix this afternoon, then head back to TX. When I get home I will disconnect the downpipe again to make one more check of the turbo, but I don't have much hope that is the problem.



With time on my hands I wondered if limiting my search for a 12 valve is necessary. For my low HP requirements would a 24 valve, with my recently serviced p-pump and a new PDR cam be worth the time and expense?

Just brainstorming. I,m not looking for more than 350.

 

[Harlacher]

I would wonder what is preventing the blow-by tube from blowing oil if it is a compression issue. With no oil coming out of it and using that much it has to be leaking somewhere. Is that not the purpose of the blow-by tube? You are cleaner down there than my truck has ever been. If I clean up that area and go for a drive when I check there is oil in the area. I don't drip but the blow-by tube is blowing excess pressure and an oil mist when I am running. Sometimes I can see the mist come up through the hood area. Never enough to use any oil and it is rare, wind blowing just right etc. I just think it is odd that you are so clean down there.

 

[fest3er]

It's clean. Too clean. But the oil's gotta be goin' somewhere. He's eliminated most everything. Except blow-by. That's why I suggested removing the filler cap. If there is a lot of blow-by, it can't all escape through the little tube. Pressure builds up in the crankcase. Oil can no longer flow down from the top of the engine to the pan. It finds someplace else to go.

And don't forget that this oil consumption may also be directly related to boost pressures. Keep the boost under 8PSI and I'll bet oil consumption goes down. But who can drive cross-country never exceeding 8PSI?

A few years ago when I found I was using a quart every 500-1,000 miles, someone suggested removing the filler cap. I did, and oil consumption dropped right back to a quart every 3-5 K miles. Since then, I've had a bit of redneck plumbing on there to keep water and dirt out and direct the oil and mist downward.

Basically, the engine is saying its rings are wore out. Pull the head, hone the cylinders and install oversize rings.

 

[GAmes]

I'm home. I did try the filler cap removal with no decrease.



While in Phoenix I discovered that if I let the engine idle for 5 minutes or more that I would get a big cloud of white (gray?) smoke when I started driving again. I also found a lot of residue on the side of the bed above the exhaust even though I have a turn down tip. I let the engine idle for a long while in the driveway when I got home. I'm thinking that possibly it is the rear seal of the turbo leaking. Instead of dropping the downpipe I will remove the turbo itself. If the exhaust housing is wet I have found the problem. I'm hoping Missouri Mule was on the right track, and having a low mileage turbo is not a guarantee of trouble free service.



More to come tormorrow.

 

[GAmes]

I pulled the turbo today. To my chagrin there was no pool of oil in the housing, not even wet. I installed my old turbo and will be driving to San Antone tomorrow to look at a 12 valve out of a '98. During the test drive today I could not duplicate the cloud of smoke after a long idle, so who knows? I'm looking at a couple hundred miles, so if the turbo is not the problem I should see some consumption. I am definitely glad that I do not have to rely on transporting to put food on the table.

 

[GaryOwen]

Just wondering if an oil sample might give some indication of the problem.

 

[GaryOwen]

Another thought is maybe engine timing is late. As I understand it, if intake valve opens late, it will cause more vacuum in the cylinder and can pull more oil past the rings. Maybe someone could explain it this is possible.

 

[GAmes]

After my drive to San Antonio I have admitted to myself that the engine is going to have to be replaced. 370 miles and another half qt of oil used. Two new threads follow.



Gary, oil analysis probably would have given me fair warning, but taking a sample now would not do any good. When I worked in helicopter maintenance we used oil sampling to identify gearboxes and engine wear. Two or three samples were used to establish a baseline, and from there abnormal wear could be recognized. Since I have no baseline a sample wouldn't do me any good, but I suspect that one taken now would show high chromium if that is what the rings are plated with.



The only timing change that I influenced is when the injector sends fuel into the cylinder. That is not related to when the valves open during operation. To change the valve timing one would have to move the cam gear to a different tooth on the crank shaft gear.

 

[HBarlow]

RIP. Too bad you only got just under 800,000 miles of wear mostly towing heavy trailers.

Six or perhaps only four Furd engines could have delivered as many miles of service and probably two or three GMs.

 

[GAmes]

Well actually I got over 800k out of it. It had a 2% error on the odometer from day one, so add 15,740, plus the 1000 or so when the odometer wasn't working. When I installed the 6 speed the odometer error increased to 3. 5%. At the very least I have 805k miles on it Instead of swapping engines I am also debating rebuilding the one I have. It would require a few more tools (like a bigger ring compressor) and would cost more, but I would know exactly what I have and not rely on the honesty of used engine sellers. A thought just occured to me, an in-frame rebuild. I know the head and the oil pan can be removed with the engine installed because I have done it. Rings and bearings only (plus a valve job). Is this a stupid idea?

 

[The patriot]

I'm thinking if you were doing all the freeze out plugs with the rebuild you'd want the engine out.

I know if it were me doing all the crawling under the truck, I'd prefer it out.

JM. 02



PS Are these engines sleeved?

 

[ewcmr2]

PS Are these engines sleeved?

No, the 5. 9 isn't sleeved.

 

[The patriot]

Thanks.



I'd also like to add that with the engine on a stand I'd be more prone to take my time and do a more careful job.

 

[ewcmr2]

Engine out also makes it really east to swap the camshaft

 

[fest3er]

Engine out also makes it really east to swap the camshaft

And fill the block. Oh, wait. He's not building a sled puller.

 

[HBarlow]

Gary,

My guess is you are your own best source of information when it comes to the rebuild decision. I doubt that 5% of Cummins 5. 9 owners have ever put 800,000 miles on one. Cummins dealer mechanics probably have lots of experience with in-frame rebuilds of larger engines but I don't know how many 5. 9s are rebuilt.

I think your challenge is going to be hauling parts if you disable your truck for a couple of weeks to rebuild it? If you do an in-frame or pull your engine and rebuild it inside a building do you have a back up truck available for hauling parts?

If you could find a good rebuildable block to rebuild while your truck is still running some of your chores would be easier to manage.

 

[Harlacher]

A long time ago I worked for a trucking (Semi) company and every 500,000 miles we had to overhaul the engines. We left them in the truck. I know much different story with all the room and stuff but it brought back memories of pulling brgs that barely looked used and replacing them. It was a planned maintenance system. Some of the Cummins looked like they had just been broken in. I hope you don't just have a leak some place, I would certainly do a compression check before I pulled it down. Why is the area around your blow-by tube so clean. That is what bothers me about all of this. 800,000 is a lot of miles but a million is such a cool number.

 

[GAmes]

I already have a PDR cam, and I do not own an engine stand capable of supporting a Cummins. I have another pickup. There are absolutely no external engine oil leaks, and I have eliminated all the easy internal sources. I wouldn't dread the job so much if it wasn't the middle of winter. It is using too much oil to work, so this may be the shortest downtime option.



Forecasts are for temps in the 20s for the next three days, and the garage is not heated. :{ I realize an attempt at in-frame is really redneck, but with a 2WD I think it is doable. Today I am going to improve the lighting, drag my '54 Ford project out and keep looking for engines in the classified ads, craigslist and e-bay.



First order of business will be pulling the head to inspect cylinder wall wear. In the grand scheme of things, not much added work if replacement of the engine becomes mandatory.



Harlacher, a couple questions. After you pulled the pistons did you hone the cylinder walls? I have a hone that fits into my drill. If so, what did you use to clean the dust off the bearing journals afterward? I am thinking copious amounts of brake cleaner.

 

[Bill Stockard]

Gary,



I've been following this thread for some time. Before I retired, I have seen Cummins N14s with high mileage (close to 1,000,000 miles or more) come into our truck shop with customer complaints about excessive oil consumption and no obvious external leaks. The engine marginally passes the Cummins blow by pressure test. On more than one occasion, upon teardown during an in-frame, the oil control rings will just about fall off the piston when it was removed. The compression rings were still good. It was apparant the oil control rings had lost their tension and were allowing more oil to pass, but not enough to create the normal tell tale oil smoke. There would be very little wear on the cylinder liners. If the cam was still good, a liner kit, bearings, and overhauling the cylinder heads would put the truck back to work.



Bill

 

[Harlacher]

Yes we would hone the cylinder walls to a nice cross hatch pattern after insuring they were in specs. Replaced all rings brgs etc whether it was needed or not. The thing was there was very little wear on the walls as a rule. We would use lots and lots of cans of engine cleaner to rinse away the dust and particles. Compressed air, rags and cleaner and lots of time. We had a saying that a good mechanic spent 60% of his time cleaning whatever he was working on. We would pull brgs that looked like they were just broke in. It was in the mid 70s and I do not remember an issue with oil rings being worn out, however it was a long time ago. I have changed professions since then so I have not stayed current. Rinse them down wipe them out and blow passages clean is what I remember.